877 research outputs found
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Energy Information Systems: From the Basement to the Boardroom
A significant buildings energy reduction opportunity exists in the office sector, given that this market segment typically is an early adopter of new technology. There is a rising trend towards smart and connected offices through the internet of things (IoT) that provides new opportunities for operational efficiency and environmental sustainability practices. Leading commercial real estate companies have begun to shift from individual building automation systems (BAS) to partially integrated and automated systems such as energy information systems (EIS). In both the United States and India, organizations are seeking operational excellence, enhanced tenant relationships, and topline growth. Hence it is imperative to engage the executives with decision-making power, by tapping into their interest in sustainability, corporate social responsibility, and innovation. This expansion of interest can enable data-driven decisions, strong energy investments, and deeper energy benefits, and would drive innovation in this field. However, none of this would be possible without robust, consistent building energy information to provide visibility across all the levels of decision making, i.e. from the basement where the facilities staff take operational action to the boardroom where the executives make investment decisions.
Price, security, and ease of use remain barriers to the adoption and pervasive use of promising EIS technologies in commercial office buildings. We believe that these barriers can be addressed through the development of ready, simplified, consistent, commercially available, low-cost EIS-in-a-box packages, that have a pre-defined set of hardware components and software features and functionality that are pertinent to a particular building sector. These simplified, sector-specific EIS packages can help to obviate the need for customization, and enhance ease of use, thereby enabling scale-up, in order to facilitate building energy savings. The EIS-in-a-box are adaptable in both U.S. and Indian office buildings, and potentially beyond these two countries
Free vibration of circular annular plate with different boundary conditions
This paper deals with the numerical simulation of free vibration analysis of a thin circular annular plate for various boundary conditions at the outer edge and inner edge. Classical plate theory is used to derive the governing differential equation for the transverse deflection of the thin isotropic plate. The finite element method is used to evaluate the first six natural frequencies and mode shapes of the thin uniform circular annular plate with radius ratios (r1/r2) for different boundary conditions. These natural frequencies results are compared with those available in the literature. The results are verified with classical plate theory with our Abaqus results and checked with the previous research literature on the topic
Literature Survey on Keystroke Dynamics for User Authentication
Behavioural biometrics is the field of study related to the measure of uniquely identifying and measuring the patterns in human activities. Computer security plays a vital role as most of the sensitive data is stored on computers. Keystrokes Dynamics is a technique based on human behaviour for typing the password. Whenever any user logins into the system, username and password combinations are used for authenticating the users. The username is not secret, and the imposter acts as user to guess the password also because of simplicity of password, the system is prone to more attacks. In this case biometrics provide secure and convenient authentication. Our system uses a Support Vector Machine (SVM) which is one of the best known classifications and regression algorithm. Support Vectors (SV) that fall under different regions is separated using hyper planes linear as well as non-linear. Researchers have proved that SVM will converge to the best possible solution in very less time
Model Predictive Control for Autonomous Driving Based on Time Scaled Collision Cone
In this paper, we present a Model Predictive Control (MPC) framework based on
path velocity decomposition paradigm for autonomous driving. The optimization
underlying the MPC has a two layer structure wherein first, an appropriate path
is computed for the vehicle followed by the computation of optimal forward
velocity along it. The very nature of the proposed path velocity decomposition
allows for seamless compatibility between the two layers of the optimization. A
key feature of the proposed work is that it offloads most of the responsibility
of collision avoidance to velocity optimization layer for which computationally
efficient formulations can be derived. In particular, we extend our previously
developed concept of time scaled collision cone (TSCC) constraints and
formulate the forward velocity optimization layer as a convex quadratic
programming problem. We perform validation on autonomous driving scenarios
wherein proposed MPC repeatedly solves both the optimization layers in receding
horizon manner to compute lane change, overtaking and merging maneuvers among
multiple dynamic obstacles.Comment: 6 page
A novel control strategy of three-phase, four-wire UPQC for power quality improvement
The current paper presents a novel control strategy of a three-phase, four-wire Unified Power Quality (UPQC) to improve power quality. The UPQC is realized by the integration of series and shunt active power filters (APF) sharing a common dc bus capacitor. The realization of shunt APF is carried out using a three-phase, four-leg Voltage Source Inverter (VSI), and the series APF is realized using a three-phase, three-leg VSI. To extract the fundamental source voltages as reference signals for series APF, a zero-crossing detector and sample-and-hold circuits are used. For the control of shunt APF, a simple scheme based on the real component of fundamental load current (I CosΦ) with reduced numbers of current sensors is applied. The performance of the applied control algorithm is evaluated in terms of power-factor correction, source neutral current mitigation, load balancing, and mitigation of voltage and current harmonics in a three-phase, four-wire distribution system for different combinations of linear and non-linear loads. The reference signals and sensed signals are used in a hysteresis controller to generate switching signals for shunt and series APFs. In this proposed UPQC control scheme, the current/voltage control is applied to the fundamental supply currents/voltages instead of fast-changing APF currents/voltages, thus reducing the computational delay and the required sensors. MATLAB/Simulink-based simulations that support the functionality of the UPQC are obtained
Control strategy for selective compensation of power quality problems through three-phase four-wire UPQC
This paper presents a novel control strategy for selective compensation of power quality (PQ) problems, depending upon the limited rating of voltage source inverters (VSIs), through a unified power quality conditioner (UPQC) in a three-phase four-wire distribution system. The UPQC is realized by the integration of series and shunt active power filters (APFs) sharing a common dc bus capacitor. The shunt APF is realized using a three-phase, four-leg voltage source inverter (VSI), while a three-leg VSI is employed for the series APF of the three-phase four-wire UPQC. The proposed control scheme for the shunt APF, decomposes the load current into harmonic components generated by consumer and distorted utility. In addition to this, the positive and negative sequence fundamental frequency active components, the reactive components and harmonic components of load currents are decomposed in synchronous reference frame (SRF). The control scheme of the shunt APF performs with priority based schemes, which respects the limited rating of the VSI. For voltage harmonic mitigation, a control scheme based on SRF theory is employed for the series APF of the UPQC. The performance of the proposed control scheme of the UPQC is validated through simulations using MATLAB software with its Simulink and Power System Block set toolboxes
Direction-dependent effects on global 21-cm detection
Cosmic dawn represents critical juncture in cosmic history when the first
population of stars emerged. The astrophysical processes that govern this
transformation need to be better understood. The detection of redshifted 21-cm
radiation emitted from neutral hydrogen during this era offers a direct window
into the thermal and ionization state of the universe. This emission manifests
as differential brightness between spin temperature and the cosmic microwave
background (CMB). SARAS experiment aims to detect the sky-averaged signal in
the frequency range 40-200 MHz. SARAS's unique design and operation strategy to
float the antenna over a water body minimizes spectral features that may arise
due to stratified ground beneath the antenna. However, the antenna environment
can be prone to configuration changes due to variations in critical design
parameters such as conductivity and antenna tilts. In this paper, we connect
the variations in antenna properties to signal detection prospects. By using
realistic simulations of a direction and frequency-dependent radiation pattern
of the SARAS antenna and its transfer function, we establish critical
parameters and estimate bias in the detectability of different models of the
global 21-cm signal. We find a correlation between the nature of chromaticity
in antenna properties and the bias in the recovered spectral profiles of 21-cm
signals. We also find stringent requirements for transfer function corrections,
which can otherwise make detection prospects prohibitive. We finally explore a
range of critical parameters that allow robust signal detection.Comment: 8 figures, 3 tables; under review at Ap
Does Healthy Living Matter to Work Outcomes? Effects of Exercise and Health Conscious Identity on Employee Job Performance and Life Satisfaction
Organizational behavior and human resource management scholarship and practice is interested in positive employee outcomes. Even though research has examined a host of work factors ranging from personality and emotions to leadership and culture, it is not clear how factors outside of work such as lifestyle influence employee performance and satisfaction. We develop theory on health conscious identity as it affect important work outcomes. We draw on emerging societal trends to outline how exercise affect employee job performance and life satisfaction. We also contend that health conscious identity has positive effect on employee job performance and life satisfaction. Our study integrates facets such as media influence, pandemic effect, and recommendations from health authorities with conventional issues of employee attitude, behavior, and well-being. Data from 280 employees and 58 supervisors supported the hypothesized relationships. We discuss implications on organizational practices in the emerging work order and suggest future research directions
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